Type A2 influenza viral infections in children.

We retrospectively reviewed the manifestations of influenza A2 in 83 hospitalized young children. Our purpose was to define the spectrum of clinical illness in this age group. Findings included fever (91%), vomiting or diarrhea (49%), pharyngitis (34%), pneumonitis (29%), otitis media (24%), conjunctivitis (13%), croup (13%), and bronchiolitis (6%). Neuromuscular manifestations occurred in 16 patients (19%) and included seizures, apnea, opisthotonos, and myositis. Three children had cerebrospinal fluid pleocytosis. Children younger than 3 months of age had fever less often and gastrointestinal symptoms more often than older children. Threee children died of progressive pneumonitis. We conclude that influenza A2 may cause a wide range of respiratory and neurologic findings in infancy and early childhood.